CHARACTERISTICS OF ALL YBA2CU3O7 EDGE JUNCTIONS OPERATING ABOVE 80-K

a-b plane YBa2Cu3O7-YBa2Cu3O7 (YBCO) edge junctions with improved properties were prepared by the use of SrTiO3 instead of BaF2 as an insulating layer in the c-axis direction. The junctions were fabricated in an all in situ laser ablation deposition process, with the barriers formed by a plasma discharge in CF4 gas. Photolithographic rather than laser ablation patterning of the junctions was used, to avoid possible laser induced damage to the films. The normal resistance of the junction decreased with T for T > 40 K, and increased at lower temperatures, indicating that carrier localization takes place in the barrier. At 80 K, a pronounced diffraction pattern of the voltage across the junction versus magnetic field was observed. Critical currents persisted up to 84 K, and under microwave radiation many Shapiro steps were observed.